Due to energy shortage crisis, development of renewable energy technologies has become an important topic. Thermoelectric conversion technology is a new renewable energy technology today which is able to directly convert between heat energy and electrical energy. In recent years, the thermoelectric conversion technology has received enormous attention from research institutions in various countries and considerable efforts have been invested in research and development. In addition to development of materials, application of thermoelectric technology has also been the focus of research interest.
A thermoelectric module is one of the products applying the thermoelectric conversion technology. Operation principles of the thermoelectric module will be described in brief as follows. As a direct current (DC) is input to the thermoelectric module, a temperature difference occurs between two terminals of the thermoelectric module, the heat energy is absorbed by the cool terminal, transmitted to the thermal terminal and exhausted from the thermal terminal, so as to achieve a heat pump capability, which is a Peltier effect. On the other hand, if the two terminals of the thermoelectric module have different temperatures, the thermoelectric module generates a direct current, and the greater the temperature difference, the higher the electric power, which is a Seebeck effect.
According to the aforementioned two principles, how to effectively perform the thermoelectric conversion effects occurring in the junction between the thermoelectric materials and the metal electrodes for application is an important subject.